Method of and apparatus for parallelizing textile fibers



y 1947. R. A. FAIRBAIRN 2,420,034

METHOD OF AND APPARATUS FOR PARALLELIZING TEXTILE FIBERS Filed April 15, 1946 Patented May 6, 1947 OFFICE METHOD OF AND APPARATUS FOR PAR- ALLELIZING TEXTILE FIBERS Robert A. Falrbairn, Needham, Mass.

Application April 15, 1946, Serial No. 662,240

12 Claims. 1

This invention relates to a method of and apparatus for disposing unafiixed unwoven textile fibers in predominantly parallel relation in a thin web or film, the present application being a continuation-in-part of my copending applications Serial No. 410,300, filed September 10, 1941, and Serial No. 465,217, filed November 11, 1942. Uses of this invention include preparing textile fibers for the removal of foreign or undesirable substances therefrom, for example, the removal of burrs, or the like from wool or other unwoven fibers or the removal of beard or kemp hairs from the down or wool fibers of cashmere, camels hair, wool and similar fleeces. Other uses will be apparent to persons skilled in the art.

By appropriately controlling the feed and the operation of a carding machine, the web or film which is produced may be controlled from a coherent web or film which varies in thickness from two or more fibers to several fibers and wherein the fibers cross and recross each other, to a film or web in which the individual fibers are separated laterally of the film or web so that the film is not coherent. A photograph of a carded web of cashmere which is of average thickness is shown in Fig, 8 of the drawing of my copending application Serial No, 410,300. The method and apparatus of this invention are adapted continuously to paralleliz the individual fibers of any carded web or film throughout its width and to advance the film of parallelized fibers for subsequent operations.

Heretofore, so far as I know, no satisfactory method or apparatus has been disclosed for continuously treating throughout its Width such a thin web or film of fibers in the form in which it emerges from a carding machine to rearrange the fibers so that they are disposed in substantially parallel relationship in the form of a thin film or web, nor to produce such a thin film which is of the order of thickness of a single fiber.

The principal object of this invention is to provide a novel method and a novel apparatus for parallelizing the fibers of a web or film of the character produced by a carding machine.

Further objects are to provide such a method and apparatus which includes means for advancing the film of parallelized fibers for subsequent operations, and which is adapted to operate upon the card web or film throughout its width.

Further objects are to provide a method and an apparatus which form a web or film which is of the order of thickness of a single fiber and in which the fibers are substantially parallel, and to provide means for advancing such a film.

Further objects will be apparent from a consideration oi. the following description and of the annexed drawings, in which several embodiments of my apparatus are chosen for the purpose of illustration.

In the drawings Fig. 1 is a diagrammatic view in elevation, illustrating the several steps in one embodiment of the method and indicating appropriate mechanical elements for performing the method;

Fig. 2 is a fragmentary plan view showing certain details of a hair-dividing apparatus;

Fig. 3 is a fragmentary plan view showing certain details of a burr-dividing apparatus;

Fig. 4 is a fragmentary plan view showing cashmere down fibers and beard hairs after they have been parallelized to a substantial extent and arranged in a film substantially one fiber thick;

Fig. 5 is a section on the lines 5-4 of Fig. 4;

Fig. 6' is a diagrammatic view illustrating another embodiment of the method and indicating appropriate mechanical elements for performing the method;

Fig. 7 is a diagrammatic view illustrating a portion of the apparatus of Fig. 1, an alternate form of moistening apparatus being shown; and

Fig. 8 is a diagrammatic view illustrating a portion of the apparatus of Fig. 1, a further alternate form of moistening apparatus being shown.

Referring to Fig. 1, which diagrammatically illustrates the various steps of the improved method, together with apparatus employed in performing certain of the steps of the method, the numeral l designates a cylinder of a card, the numeral 2 designates the dofier cylinder of the card, and the numeral 3 indicates an endless conveyor belt which may have a smooth surface and which is suitably supported by and driven by the rolls 4. The conveyor belt 3 is designed to receive and to advance the thin web or film F from the dofier roll 2 of the card. A vibratory comb C peels the film from the doffer roll.

When the web or film F is thin it has a strong tendency to adhere to the dofier r011 2, especially if the air in the room has a low relative humidity. In order to insure satisfactory delivery of the web or film from the doiler roll to the upper run of the conveyor 3, there may be provided a di-electrifying apparatus, indicated generally by the numeral 5, and here shown as associated with the comb C. This apparatus may be of a known commercial type supplied, for example, with alternating current at cycles and producing a potential of 14,000 volts or the like, and comprises a discharge device disposed close to the surface of the dofler roll, and is operative to neutralize the effect of any electrical charge within the fleece or film.

The web or film F which is carried by the upper run of the conveyor 3 is moved to the right, as viewed in Fig. 1, and delivered to the rolls l6 and 'l of the parallelizing apparatus. These rolls are each of suificient length to receive the complete width of the web or film F produced by the card; the roll I may be made of steel, and the roll i6 rubber covered. As shown in Fig. 1, the surface of the roll l6 bears against the conveyor belt 3 and continuously removes the film or web F from the surface of the conveyor belt 3.

The roll I6 is rotated in a counterclockwise direction, looking at Fig. 1, and preferably at a surface speed which is not less than the surface speed of the conveyor belt 3. The roll 1 is rotated in a clockwise direction looking at Fig. 1,

' and at a faster surface speed that the surface speed of the roll IS. The rolls 1 and I6 preferably are constructed and mounted so that a substantially uniform pressure is exerted by the surface of one roll against the surface of the other roll throughout its length, and preferably they are mounted so that the amount of such pressure may be varied for webs of different thicknesses or materials. Preferably the roll I6 is resiliently urged against the roll 1 by a spring or springs so that the roll 16 will yield to permit the passage of a thicker than normal accumulation of fibers through the bite of the rolls.

In accordance with this invention either the fibers themselves, the roll H5, or the roll I are moistened so that when the fibers engage or are engaged by the surface of the roll 1 a thin film of moisture is presented between each fiber and the surface of the roll, causing each fiber to tend to cling to the surface of the roll but permitting the fiber to slide or slip both laterally and iongitudinally when the surface is moved at a greater speed than that of the fiber. I

In Figs. 1, 7 and 8 three alternate methods of moistening are illustrated. I

In the apparatus illustrated in Fig. l, a reservol;- I! containing water or other liquid I3 is provided. The surface of the roll I continuously picks up a thin film of fluid from the reservoir i2, and the scraper roll ll, which is rotated in'a counterclockwise direction, looking at Fig. 1, uniformly distributes the fluid over the surface of the roll I and returns the excess fluid to the reservoir. Thus as the fibers leave the bite of the rolls I8 and I! they cling to the moist surface of the faster moving roll 1.

In the embodiment illustrated in Fig. '7 the reservoir l2 and the scraper roll it are omitted and a spray header Si is mounted above the film F and extends transversely thereof throughout its width and throughout the width of the conveyor belt 3. A series of finely adjustable nozzles 9 are mounted at spaced intervals on the spray header Si. The nozzles are adjusted so that they continuously emit a fine spray of water or other fluid. This spray moistens the film or web 1? throughout its width and the film or web in turn moistens the surfaces of the rolls l6 and 1.

Thus as the fibers leave the bite of the rolls IB' and I they cling to the moist surface of the faster moving roll i.

In the apparatus illustrated in Fig. 8 of the drawings a spray header 3-2 is mounted above the roll l6 and extends transversely of the machine substantially parallel to the axis of the roll IS. A series of finely adjustable nomles I are mounted at spaced intervals on the spray header 8-2. The nozzles are adjusted so that they continuously emit a fine spray of water or other fluid. This spray moistens the surface of the roll 16 throughout its length and the roll II in turn moistens the film or web F and the film or web in turn moistens the surface of the roll 1. Thus as the fibers leave the bite of the rolls [6 and 1 they cling to the moist surface of the faster movingroll'l.

The brush i1 is rotated in a clockwise direction, looking at Figs. 1, I and 8, it engages the surface of the roll I throughout its length, and it removes the film of fibers from the surface of the roll I.

As the forward end of each fiber progresses beyond the bite of the rolls 1 and ii, the moist surface of the faster moving roll 1 causes" the forward end of the fiber to straighten out to a position in which it xtends substantially perpendicular to the bite of the rolls 1 and l 6. During such action the forward movement of the fiber. is retarded by the slower moving roll it which engages the trailing end of the fiber and the forward end of the fiber clinging to the moist surface of the roll 1 slides on this surface until it has assumed a direction substantially parallel to the direction of movement thereof, which is a direction substantially perpendicular to the bite of the rolls l6 and I at the point where its trailing end is engaged by the roll Hi. This aligning action continues until the trailing end of the fiber leaves the bite of the rolls I and i8 and the fiber is then carried forward by the surface of roll I, the film of moisture then serving retain it thereon in its aligned position. Eac of the fibers in the web or film F is thus arranged in substantially parallel relationship and in a film which is of the order of thickness of a single fiber.

It has been found that the moist surface of the roll 1 serves as an ideal medium for parallelizing and advancing a film of parallelized fibers which are naturally very crinkly or curly. For example, in working with a web or film of cashmere fibers, the down fibers of which are extremely crinkly, the fibers are held in aligned relationship on the surface of the roll I after they have been freed from the bite of the rolls 1 and i6, and they do not recurl or recrinkle thereby losing or disrupting the parallelized relationship as would be the case if the fibers or the surface of the roll I were not moistened or otherwise treated to cause the fibers to cling thereto. For example, if the machine is stopped and the fibers and the surface of the roll I are dried, the fibers immediately crinkle, separate from the surface of, the roll and lose their parallel relationship. A film of substantially parallelized cashmere fibers is illustrated in Figs. 4 and 5, the fine fibers being down fibers and the coarse fibers bein beard hairs.

The roll 8 illustrates one form of apparatus which may be utilized for subsequent treatment of the parallelized fibers on the surface of the roll I. In Figs. 1 and 2 the surface of the roll 8 is furnished with dividing elements, for example a plurality of steel wires 8" of small diameter wrapped helically about the surface of the roll. These wires may be of circular cross section and they are preferably of the diameter of the order of approximately 0.01". The roll 8 is mounted in suitable bearings capable of micrometer adiustment, so as to vary the distance between the peripheries of the rolls 1 and 8 with extreme accuracy whereby the pressure exerted by the dividing elements or wires 8 upon the surface of the rolls 1 may be delicately adjusted. The bite or the rolls 8 and I is located a distance from the bite of the rolls I and I8 which is greater than the average length of the particular fibers being run, so that a fiber is not gripped by both bites at the same time. This apparatus has been found to be of great value in cutting or dividing beard or kemp hairs into short sections without substantially damaging the down or wool fibers of cashmere, wool and the like, so that the short sections of beard hairs may be separated from the longer down fibers. A more detailed description of this dividing apparatus will be found in my copending application Serial No. 410,300, filed September 10, 1941.

In Fig. 3 the roll 8 is provided with a dividing element or wire 8'', which extends substantially perpendicular to the axis of the roll 8. This wire may also be of a diameter of approximately 0.01". It may be arranged on the surface of the roll 8 for example by winding two wires around the surface of the roll and then removing one of the wires, thus leaving the turns of the wire 8* spaced apart approximately 0.01 between adjacent edges, or 0.02 from center line to center line. As in the hair dividing apparatus illustrated in Fig. 2, the surfaces of the rolls 8 and I are ground with extreme accuracy both longitudinally and concentric with the bearing surfaces so that the dividing surface of the wire 8 exerts a uniform pressure against spaced portions of the surface of the roll I which it engages during each complete revolution of the rolls I and 8. -The roll 8 i also mounted in suitable bearings capable of micrometer adjustment so as to vary the distance between the peripheries of the rolls 1 and 8 with extreme accuracy, thereby adjusting the pressure of the wire 8 upon the surface of the roll I. This form of roll may be utilized 'in dividing burrs or other vegetable matter into small segments so that in a subsequent operation such segments may be separated from the wool or other fibers. Since the fibers pass into the bite of the rolls 8 and I in substantially parallel relationship and extend substantially perpendicular to their bite, most of 'the fibers pass between the turns of wire 8 without being operatively engaged by the wire. The few fibers which do not thus pass normally between the turns of the wire 8" are not substantially damaged or substantially cut first because the pressure of the wire 8 upon the surface of the roll I (through the fibers), while sufilcient to cut or break the thicker burrs, is insufiicient to crush or divide the majority of the finer fibers (since the pressure of the wire 8 upon the surface of the roll I is delicately adjusted), and second because when engaged by the wire the fibers tend to slip or slide laterally of the surface of the roll I and some of them are thus caused to pass between the turns of the wire 8".

In the apparatus illustrated in Fig. 6 of the drawings the card web or film F' is conveyed from the doffer by the conveyor belt 3 which passes around the periphery of the driven roll 20. The card web is fed from the conveyor belt to the bite of the rubber covered roll 2| and the parallelizing roll I. The parallelizing roll! is continuously rotated in a clockwise direction, looking at Fig. 6. The roll 2| and the rubber covered roll or brush 22 are continuously rotated in a counterclockwise direction, looking at Fig. 6.

The roll 2| engages the surface of the rolls 1 and 22. The roll 22 enga es-the surface of the roll 2| but does not engage the surface of the rolls I and 8. The bite of the rolls 2| and I is preferably located at a greater distance from the bite of the rolls 8 and 1' than the average length of the fibers which are being treated. The roll 2| may be rotated at substantially the same surface speed as the surface speed of the conveyor belt 2 or at a greater surface speed. The roll or brush 22 is rotated at a greater surface speed than that of the roll 2| and it serves to return to the surface of the roll 'I' any fibers which may adhere to the surface of the roll 2|. The roll l is rotated at a greater surface speed than that of the roll 2|. A rubber covered roll or brush 23 engages the surface of the steel roll 1'. It is rotated in a clockwise direction, looking at Fig. 6, and at a surface speed substantially equal to the surface speed of the roll I. It serves to remove the fibers from the surface of the roll 1'. The length of each of the rolls 2|, 22 and I is at least equal to the width of the web or film F produced by a card which may customarily vary from 48 to 60 inches.

The moisture may be supplied to the surface of the roll 1* by a reservoir I2 which carries a body of water l8, the reservoir being of substantially the same length as the roll I. In use of the reservoir I2, a'sheet of fibrous material 24, for example closely compacted, degreased, wool felt, transfers the water from the reservoir l2 to the surface of the roll 'I", and thereby continuously applies to said surface a thin coating or film of moisture. The characteristics of this film may be controlled by adjustment of the set screws 25 to increase or decrease the pressure of the fibrous material against the surface of the roll I or by adjustment of the nuts 26 to increase or decrease the pressure of the crossbar 21 against the surface of the fibrous material.

Instead of the reservoir l2 and the sheet of fibrous material 24 spray headers may be utilized. For example a spray header identical to the spray header S| illustrated in Fig. 7 of the drawings may be mounted transversely of the machine above the web or film F thereby to moisten the film or web F throughout its width, whereby the surface of the roll I is moistened throughout its length. Alternatively a p ay header identical to the spray header S 2 illustrated in Fig. 8 of the drawings may be mounted above the roll 2| extending transversely of the machine substantially parallel to the axis of the roll 2|, and this spray header may be operated continuously to moisten the surface of the roll 2| whereby the film F is moistened and it in turn moistens the surface of the roll 1 throughout its length.

The required amount of moisture depends upon the amount of stock which i being treated during any interval of time, and upon the character of the fiber which is being treated; The place and manner of application of the moisture is believed to be immaterial so long as a sufficient amount of moisture is evenly distributed across or throughout the length of the surface of the roll I to cause the fibers to cling to the surface of the roll 1* as they leave the bite of the rolls 1 and 2|.

The roll 8 is preferably driven in a counterclockwise direction, looking at Fig. 6, and at substantially the same surface speed as that of the roll I. The roll 8 may be provided with dividing elements similar to those shown in Fig. 2 or with a dividing element similar to that shown in Fig.

3-, or it may be merely a smooth surfaced roll serving to crush burrs or other foreign matter in the material being treated, thereby reducing it to small particle size. I

The roll 2| serves to retard the relative speed of forward movement of the fibers and the faster moving roll 1- serves to parallelize the fibers, to reduce the thickness of the film or web, to retain the fibers in parallelized relationship, and to convey them forwardly in such relationship. In this respect the roll 2| is the equivalent of the roll it of Fig. 1, and the roll 'I' is the equivalent of the roll I of Fig. 1. A

The degree to which the fibers are parallelized, the thickness of the film of parallelized fibers, and the distance between the parallelized fibers depends primarily upon the relative surface speeds of the rolls 1 (or 1) and It (or 2!). By appropriate adjustment of these relative speeds and corresponding adjustment of the moistening means, a film having the desired characteristics may be produced upon the surface of the rolls 1 or 1" from any web or film produced by a card.

The scope of this invention is in no way limited relative to the operations which may be performed after the parallelizing step. The disclosure of the rolls 8 and 8 and of the dividing elements I and I is solely for the purpose of illustrating two subsequent operations which may be utilized.

The scope of this invention is not intended to be limited to the use of a cylinder or roll as the parallelizing element, for example, an endless belt or apron may be substituted for the rolls 1 or 1'. The scope of the invention is not intended to be limited to the use of a cylinder or roll as the retarding element. For example, an endless belt or even a stationary member may be substituted for the rolls It or 2|. In utilizing such a stationary member, however, it should preferably be capable of delicate adjustment so that the pressure exerted by it upon the fibers is capable of variation over a substantial range to appropriately retard the relative speed of advancement of fibers or webs of varying thicknesses as it applies them to the faster moving parallelizing element.

The claims hereof are directed to those aspects of the method and apparatus which relate solely to reducing the thickness of the web or film, parallelizing the fibers or advancing the resultant web or film, and other aspects of the disclosure are claimed in my said co-pending applications Serial No. 410,300 and Serial No. 465,217 and in my co-pending application Serial No. 713,768, filed December 3, 1946,

While I have shown and described one desirable method and several desirable embodiments of apparatus embodying my invention, it should be understood that this disclosure is for the purpose of illustration only and that various forms of the apparatus may be used and that the substitution of equivalent steps in the method may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

1. The method of treating unwoven textile fibers comprising the steps of advancing at a predetermined speed a-film or web of fibers of the character of a film or web produced by a carding machine, causing the fibers to cling to a surface in the presence of moisture and, while the fibers continue to cling to said surface, advancing said surface at a higher surface speed than the surface speed of the firm or web whereby the faster moving surface causes the fibers to extend in a direction predominantly parallel to its direction of movement, reduces the thickness of the film or web to substantially single fiber thickness and retains and advances the fibers in said relationship.

2. The method of treating unwoven textile fibers comprising the steps of advancing at a predetermined speed a film or web of fibers of the character of a film or web produced by a carding machine, causing the advanced portions of the fibers to cling to a surface in the presence of moisture, and, while the advanced portions of the fibers continue to cling to said surface, advancing said surface while retarding the speed of forward movement of the trailing portions of the fibers, whereby the faster moving surface causes the advanced portions of the fibers to extend in a direction predominantly parallel to the direction of movement of said surface, reduce the thickness of the film or web to substantially single fiber thickness and retains and advances the fibers in said relationship.

3. The method of treating unwoven textile fibers comprising advancing at a predetermined speed a film or web of fibers of the character of a film or web produced by a carding machine, causing a portion of each fiber to cling to a surface in the presence of moisture, and, while said portion of the fiber continues to cling to said surface, advancing said surface while retarding the speed of forward movement of another portion of the fiber, whereby the portion of each fiber which clings to said surface is caused to extend in a direction predominantly parallel to its direction of movement, the thickness of the film or web is reduced to substantially single fiber thickness and the fibers are retained and advanced in said relationship.

4. The method of treating unwoven textile fibers, comprising the steps of forming the fibers into a web or film by carding, advancing the web or film, causing the advanced portions of the fibers to cling to a surface in the presence of moisture and, while the advanced portions of the fibers continue to cling to said surface, advancing said surface while retarding the speed of forward movement of the trailing portions of the fibers, whereby said surface causes the fibers to extend in a direction predominantly parallel to its direction of movement, reduces the thickness of the film or web to substantially single fiber thickness and retains and advances the fibers in said relationship.

5. The method of treating unwoven textile fibers comprising the steps of forming the fibers into a web of the character of a web produced by a carding machine, advancing the web at a predetermined speed, causing the advanced portions of the fibers to cling to a surface in the presence of moisture, advancing said surface at a higher surface speed than the surface speed of the trailing portions of the fibers while the advanced portions of the fibers continue to cling to said surface, whereby said surface causes the advanced portions of the fibers to extend in a direction predominantly parallel to the direction of movement of said surface, reduces the thickness of the film or web to substantially single fiber thickness and retains and advances the fibers in said relationship.

6. The method of treating unwoven textile fibers comprising the steps of advancing at a predetermined speed a film or web of fibers of the character of a film or web produced by a carding machine, passing said film or web into the bite of a pair of rolls, one of said rolls having'a surface speed greater than that of the other and having a moist surface to which the fibers tend to cling,

and causing the fibers to continue to cling to the surface of said faster moving roll until after their trailing portions have left said bite, whereby said fibers are caused to extend in a direction substantially parallel to the direction of movement of said surface, the thickness of the film or web is reduced to substantially single fibered thickness and the fibers are retained and advanced in said relationship.

7. The method of treating unwoven textile fibers comprising the steps of forming the fibers into a web of the character of a web produced by a carding machine, advancing the web at a predetermined speed and, as the web is advanced, causing the fibers thereof to cling to a faster moving surface in the presence of moisture, whereby the faster moving surface aligns the leading portion of each advancing fiber in the web substantially parallel to the direction of movement of the faster moving surface, reduces the thicknes of the film or web to substantially single fiber thickness and retains and advances the fibers in said relationship.

8. The method of treating unwoven textile fibers comprising advancing at a predetermined speed a film or web of fibers of the character of a film or web produced by a carding machine, moistening the film or web, passing the moist film or web to the bite of a pair of rolls and rotating one of said rolls at a greater surface speed than that of the other, whereby the moisture and said reater surface speed cause the fibers to cling to the surface of said faster moving roll until after their trailing portions have left said bite.

9. In apparatus of the class described including means for advancing at a predetermined p ed a web or film or unwoven textile fibers of the character of a web or film produced by a carding machine, the improvement which comprises a parallelizing member having a surface engageable with advanced portions of said fibers while trailing portions of the fibers remain in engagement with said advancing means, means operative to moisten the surface of said parallelizing member, means for advancing the surface of the parallelizing member at a higher surface speed than that of the fibers thereby to cause the fibers to cling to said surface and means to remove the fibers from the surface of the parallelizing member after the trailing portions of the fibers have discontinued engagement with said advancing means, whereby the constituent fibers of the web or film are caused to extend in a direction predominantly parallel to the direction of movement of said parallelizing member, the thickness of the web or film is reduced to substantially single fiber thickness and the fibers are retained and advanced on the surface of said parallelizing member in said relationship.

10. In apparatus of the class described includin: means for advancing at a predetermined speed a web or filnaofunwoven textile fibers of a character of a web or film produced by a, carding machine, the improvement which comprises a fiber retarding member having a surface en- 10 gageable with said fibers, a parallelizing member having a, surface engageable with advanced portions of said fibers while trailing portions thereof remain in engagement with said retarding member, means operative to moisten the surfibers, whereby the advanced portions of the con- 1 stituent fibers of the web are progressively parallelized and the thickness of the web is progressively reduced to substantially single fiber thickness while the trailing portions of the-fibers are retarded by said retarding member and the fibers are retained and advanced on said surface in said relationship after the retarding member has discontinued engagement with the trailing portions of the fibers.

11. An apparatus of the class described, said apparatus including a pair of rolls turning in opposite directions at different surface speeds. means operative to present a web or film of fibers to the bite of said rolls, means to moisten the surface of the roll which has the greater surface speed 7 thereby to cause the fibers to adhere to the surface of said faster moving roll until after their trailing ends have left said bite and means to remove the fibers from the surface of said faster moving roll after their trailing ends have left said bite.

12. An apparatus of the class described, said apparatus being of the kind wherein a card reduces the fibers to the form of a web or film, the improvement which comprises fiber parallelizing means comprising a pair of rolls into whose bite the web or film is advanced, one of said rolls having a substantially higher surface speed than that of the other roll, means operative to moisten the surface of the roll having the higher surface speed, whereby the constituent fibers of the web or film cling to said latter roll after they leave the bite of the rolls, thereby causing the fibers to extend in a direction predominantly peripheral of the moistened roll, and means to remove the fibers from the surface of the roll having the higher surface speed after their trailing ends have left said bite.

ROBERT A. FAIRBAIRN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 307,161 Bailley Oct. 28, 1884 1,905,268 Cotchett Apr. 25, 1933 2,323,167 Varga June 29, 1943 FOREIGN PATENTS Number Country Date 1,430 British 1880 481,550 British Mar. 14. 1938 Certificate of Correction Patent No. 2,420,034. May 6, 1947.

, ROBERT A.FAIRBAIRN It is hereby certified that errors appear in the printed specification'of the above numbered patent requiring correction as follows: Column 3, line 21, for that read than; column 7, line 75, claim 1, for firm read film; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 1st day of July, A. D. 1947.

LESLIE FRAZER,

First Assistant Commissioner 0 f Patents. 

